Abstract
BackgroundThymic carcinoma is a rare cancer with minimal evidence of a survival benefit following chemotherapy. An oral fluoropyrimidine of S-1, however, is the recommended active cytotoxic chemotherapy agent for refractory thymic carcinoma based on a case series, whereas sunitinib or everolimus are recommended as molecular-targeted agents based on Phase II trials. We retrospectively investigated the efficacy of S-1 for refractory thymic carcinoma and performed a biomarker analysis.MethodsWe assessed the clinicopathological variables of 14 consecutive patients who underwent S-1 for refractory thymic carcinoma and correlated the clinical outcomes with potential biomarkers using paraffin-embedded cancer tissues of eight patients in the cohort.ResultsA total of 178 thymic malignancies were identified, of whom 14 patients included 12 cases of squamous cell carcinoma, one lymphoepithelioma-like carcinoma, and one undifferentiated carcinoma. Six patients exhibited a partial response (42.9 %: 95 % confidence interval [CI], 21.4–67.4) and the disease control rate was 85.7 % (60.0–96.0 %). After a median follow-up of 24.2 months, the median progression-free survival was 8.1 months (range, 2.6–12.2 months), and median overall survival was 30.0 months (range, 6.2–41.9 months). No significant correlation between biomarker expression and response was noted. However, thymidine synthase (TS)/dihydropyrimidine dehydrogenase and TS/orotate phosphoribosyltransferase were observed.ConclusionsS-1 for refractory thymic carcinoma offered clinical activity and achieved an 85 % disease control rate. Although the biomarkers did not correlate with clinical outcome, the study results showed efficacy of S-1 as a cytotoxic chemotherapy for refractory thymic carcinoma, which warrants future investigation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2159-7) contains supplementary material, which is available to authorized users.
Highlights
Thymic carcinoma is a rare cancer with minimal evidence of a survival benefit following chemotherapy
Thymic malignancies comprising of thymoma and thymic carcinomas are rare cancers according to the above definition
Retrospective studies have shown types A and AB to have better prognoses than B1, B2, B3, and carcinomas, with thymic carcinoma in particular having a poor prognosis compared with thymomas, with a 5-year survival rate of 30–50 %. [7,8,9] The Masaoka–Koga staging system is widely accepted for both thymomas and thymic carcinomas, but this can lead to incorrect diagnoses, confusion between clinical entities, and mixing of management strategies
Summary
Thymic carcinoma is a rare cancer with minimal evidence of a survival benefit following chemotherapy. Thymic malignancies comprising of thymoma and thymic carcinomas are rare cancers according to the above definition. Advanced stages at initial diagnosis are demonstrated in thymic carcinoma with metastasis or extension to surrounding tissues, whereas immune-active complications appears at early stages in thymoma. Retrospective studies have shown types A and AB to have better prognoses than B1, B2, B3, and carcinomas, with thymic carcinoma in particular having a poor prognosis compared with thymomas, with a 5-year survival rate of 30–50 %. [7,8,9] The Masaoka–Koga staging system is widely accepted for both thymomas and thymic carcinomas, but this can lead to incorrect diagnoses, confusion between clinical entities, and mixing of management strategies. Patients with metastatic thymic carcinoma are treated with palliate-intent chemotherapy or best supportive care. Platinum combination chemotherapy with or without anthracycline is a widely used chemotherapy for thymic carcinoma as firstline chemotherapy, with response rates ranging from 20– 50 % [10, 11]
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